Table 5 11 

 Waves and Current Potential Sediment-Transport Rates || 



Htr 



m 



r 



s 



Transect C4 



Transect C5 



Transect C6 



Transect C7 



Transect C8 | 



Qi 



m^/year 



±20 



m^/year 



Oi 

 m'/year 



±20 



m'/year 



Oi 

 m^/year 



±20 



m^/year 



Qi 



m^/year 



±20 

 m^/year 



a, 



m^/year 



±20 

 m'/year 



1.07 



4 



51,500 



10,300 



70,900 



14,200 



40,600 



8,120 



58,000 



11,600 



43,200 



8,630 



2.19 



6 



40,800 



8,160 



56,100 



11,200 



32,100 



6,430 



45,900 



9,180 



34,200 



6,840 



3.73 



7.9 



35,600 



7,120 



48,900 



9,790 



28,000 



5,610 



40,000 



8,010 



29,800 



5,960 



4.66 



8.6 



42,400 



8,470 



58,200 



11,600 



33,400 



6,670 



47,600 



9,530 



35,500 



7,090 



5.36 



9.2 



7,470 



1,490 



10,300 



2,050 



5,880 



1,180 



8,400 



1,680 



6,250 



1,250 



0.63 



4 



15,900 



3,180 



21,800 



4,370 



12,500 



2,500 



17,900 



3,570 



13,300 



2,660 



1.21 



5 



18,600 



3,710 



25,500 



5,110 



14,600 



2,920 



20,900 



4,180 



15,500 



3,110 



1.83 



6 



9,170 



1,840 



12,600 



2,520 



7,220 



1,450 



10,300 



2,060 



7,680 



1,540 



2.29 



6.5 



17,000 



3,400 



23,400 



4,680 



13,400 



2,680 



19,100 



3,830 



14,200 



2,850 



2.62 



7 



4,320 



864 



5,940 



1,190 



3,400 



680 



4,860 



972 



3,620 



724 





242,760 



48,534 



333,640 



66,710 



191,100 



38,240 



272,960 



54,612 



203,250 



40,654 



Historic Records 



Historic shoaling and dredging information from USCG records provide some 

 limited data on sediment transport at Port Huron. In 1978, the Detroit District 

 submitted a letter to the USCG stating that sediment transport at Port Huron was 

 expected to be similar to that at Port Sanilac 48 km (30 miles) to the north. 

 Studies at Port Sanilac indicated that net transport was to the south at 

 23,000 cu m/year (30,000 cu yd/year). Shoaling in Port Sanilac Harbor was 

 2,300 to 4,600 cu m/ year (3,000 to 6,000 cu yd/year). Geographically, there are 

 few hydraulic (and thus sediment-transport potential) similarities between 

 Port Sanilac and Port Huron. Port Sanilac is far enough north that it is beyond the 

 influence of Lake Huron discharge into the St. Clair River. Though the wave 

 climates may be similar at the two locations. Port Huron is so far south in 

 Lake Huron that wave approaches are more narrowly bounded from the north to 

 northeast directions. In addition, the boat basin at Port Huron is located at a 

 critical shoreline orientation change — shores south of the boat basin run along an 

 azimuth of approximately 205 deg (along the direction of the St. Clair River), 

 while shores north of the boat basin (including Port Sanilac) run approximately 

 160 deg. This critical orientation change this far south in Lake Huron wiU have 

 significant impacts on wave propagation direction and sediment transport relative 

 to the shoreline. 



Limited information from dredging records at the boat basin provides little 

 insight into shoaling and transport rates. Reliance on these data must be viewed 

 with skepticism because previous boat basin configurations doubtless influenced 

 the amount of sedimentation — encouraging deposition in some cases or 

 discouraging it in others. In addition, there is no way to know what dredging 

 volumes are "maintenance" dredging, i.e., removal of material that has 



28 



Chapter 5 Sediment Transport 



